bluebird boxes: be a good landlord
THE NEIGHBOR WHO HANGS BAGS of giant homegrown shallots on my gate also has rules and regulations. “Bluebird Rules and Regulations,” to be specific, as in: How to be a good bluebird landlord, minimizing hazards for the beloved birds with specific nestbox tips and tricks.
Deb, my “next-door” neighbor despite the uphill mile of dirt road between us, installed her first nestbox 12 years ago. Today, she has a trail of 24 boxes on her farm in Columbia County, New York, where she spends much of bluebird season (here, that’s March through August) “worrying over my little charges,” she says.
q&a: deb’s bluebird rules and regulations
Q. Where did you learn to be a good bluebird landlord?
A. I rely heavily on Bet Zimmerman’s website Sialis.org [Sialis is Latin name for the bluebird’s genus] and a wonderful little pamphlet called “Enjoying Bluebirds More” by Julie Zickefoose, and I always urge (implore, really) people interested in putting up nestboxes to read Bet’s page of bottom-line advice for new bluebirders.
Q. So what’s the basic thrust of your Bluebird Rules and Regulations?
A. My boxes are installed to encourage successful nesting by the bluebirds by minimizing the many threats they face throughout their season. Before nesting season even begins, I make sure my boxes are cleaned from the previous season.
I also apply a coat of Ivory soap to the ceiling to prevent wasps’ nests, and I attach a bit of plastic netting to the inside of the box opening to serve as a “kerf” (a little ladder that fledging bluebirds can climb to reach the exit hole, photo below).
Then I do a little dance to bring good luck because, well, you never know. Last week, as I was rubbing Ivory soap on the ceilings of my 24 boxes, I was thinking how amazing it is that these beautiful creatures survive at all considering the many threats they face while nesting. Here are a few:
- Aforementioned wasps’ nests;
- Blowfly larvae who feed on nestlings during prolonged rains or drought;
- Raccoons, snakes and rats who steal eggs and kill nestlings;
- Cats who stalk;
- Competition from tree swallows and wrens;
- Nestlings that are unable to climb out of the box at fledging time (necessitating those “kerfs” I mentioned earlier);
- And most dire of all, the dastardly house sparrow.
Q. What’s the key to success, if there is one? Sounds like a lot of possible trouble can occur.
A. The most important advice I can offer is to use a nestbox specifically designed for bluebirds, locate it properly and monitor it throughout the nesting season.
Spring comes, we hear that cheerful throaty song and we are moved to put up a home for the bluebird. We rush to buy a birdhouse, nail it to a fence post and think we have done a good deed for the bluebirds. If your readers take away only one idea it is this: An improperly located and unmonitored nestbox will quickly become a bluebird death trap.
Q. How do we avoid that?
A. Bluebird Rule #1: Resist all temptation to hammer a box onto the nearest tree, the side of a building or fence post. Doing so will almost certainly bring disaster to the bluebirds and heartache to you.
A raccoon, rat or snake can easily climb that wooden post to steal eggs and kill nestlings. Instead, your nestbox should ideally be mounted on conduit pipe that a raccoon can’t easily climb, fitted below with a baffle or predator guard (photo below; predator guards can be made from stove pipe) and located in an open, grassy area at least 100 feet away from shrubs or other natural “cover.” Nestboxes should face away from prevailing winds, which generally means facing south. If you are lucky enough to have tree swallows, you will want to have a pair of nestboxes, back to back, about 15 to 25 feet apart (like in the top photo).
Then, follow Bluebird Rule #2: Do everything possible to prevent house sparrows from invading. Bet Zimmerman says on her website, “Successful bluebird landlords do not tolerate house sparrows…which are non-native nest site competitors. In my opinion, it is better to have no nestbox at all than to allow house sparrows to breed in one.”
I agree and I think it bears repeating: It is better to have no nestbox at all than to put one up where there are house sparrows, which are invasive alien predators and one of only a few bird species that are not protected by the Migratory Bird Act of 1918. (The European starling is another species not protected by this Federal law, but it is too big to fit into the entry hole of a properly sized bluebird nestbox. The house sparrow, on the other hand, is smaller than a bluebird and can easily fly into the box.)
Q. What are signs of house sparrow invasion?
A. The first is a trashy-looking nest that includes weeds, straw, and garbage in a big arc curving up the back of the box. The second–and most disturbing–sign is a dead bluebird inside the box. If you find a dead bird inside the box, chances are very, very high that it was trapped and killed by a marauding house sparrow. Bet recommends a number of ways to manage house sparrows.
Q. So besides proper siting, the right box, and reckoning with house sparrows, what other care is essential to being a good landlord?
A. Bluebird Rule #3: Once erected, monitor your nestbox. To quote from “Enjoying Bluebirds More:”
“A bluebird box put up and never monitored is like a letter never sent.”
In addition to monitoring for house sparrows, I also watch for blowfly larvae, which suck on nestlings during prolonged periods of stressful weather conditions like drought or rain. I even keep a spare dry nest on hand to swap out if a nest gets wet or infested (but I admit I do not recommend this for the inexperienced bluebirder).
I also watch very carefully for the first bluebird egg. Once that first egg has been laid, nothing will keep the female out of the nestbox, so that is when I put up a sparrow spooker (above and below)–basically a stick with lots of reflective streamers hanging off it. The flapping, blowing streamers scare the house sparrows and deters them from entering. (If I were to put up the sparrow spooker before the bluebird lays her first egg, she too would be deterred from using the box, so I only put it up after that first egg is laid.) Really good instructions for making a sparrow spooker are here.
Q. Beyond the box regimen, are there other rules we need to follow?
A. The last (but not least) important advice I have is really up your alley, Margaret, and that is to create a backyard paradise by planning and planting for bluebirds.
To quote again from “Enjoying Bluebirds More:” “What use is a bedroom if there is no kitchen?”
Bluebirds, like all other wild species, are under increasing pressure from habitat loss. Planting fruiting trees and shrubs helps the bluebirds thrive year-round. Because bluebirds have a fondness for ground-hugging prey, every time we mow our lawn, we create ideal foraging conditions for bluebirds. Water is also a great lure for bluebirds who love to bathe, even daily.
Q. Any last words?
A. Nothing makes me happier than seeing fledglings leave the box for the first time. I wish all of your readers great success in their careers as bluebird landlords. And, may all your blues be birds!
(All photos by my neighbor Deb, used with permission.)
Shirley Halverson says
I have native Douglas squirrels that take over just about every nest box I have. They climb metal pipe up & down like they have velcro feet. If I put a box under eaves of a shed, they just climb the siding. They enlarge the birdhouse holes & fill the boxes with insulation & leaves. I’ve put metal barriers around the holes and they can’t get in, but still harass nesting birds. Sometimes they just make another hole between the roof & side of the box to get around the one I alter. I try to be a backyard wildlife sanctuary, but these squirrels are making me say “Uncle”. (Washington State)
margaret says
Hi, Shirley. I have to admit I am not much of a squirrel lover! What wild monkeys they are, and so clever. The important things for the birds (as well as to keep squirrels out) is never to put boxes on trees or buildings, but rather on regulation poles with the serious baffles like in the photo, and out in the open. Sounds like you would need metal poles. I do find that boxes on poles out in the open and with the proper metal baffle defeat them.
Joe Doran says
I have used the baffle on a wooden pole for five years and have yet to see a squirrel get by it and it is a bird feeder. I have watched two squirrels , tails flipping, scratch themselves in frustration. It is about half the length of your pictured. A bit longer than a large juice can which I purchased at a bird supply store.
Rudy says
What size hole for a bluebird.
margaret says
The Sialis bluebird website has a set of dimensions to refer to.
Shawn says
It’s also important to have a tree or shrub about 10 to 15 feet away from bluebird boxes. These provide a landing pad as it were for fledglings leaving the nest. The boxes in the photos above are not located properly — they’re WAY too far away from nearby trees.
Ellen B says
Shawn, aren’t those two boxes a bit too close together, too? Thanks for the info. And Margaret and Deb, a HUGE thanks for the article!
margaret says
Both Sialis.org and Cornell Nest Watch say open areas, and like 300 feet from scrubby brushy vegetation that attracts the dreaded house sparrows. However that’s for our Eastern species — the Western bluebirds does NOT want open areas like that, Sialis clarifies. Sialis says paired boxes can be 5-20 feet apart (some references even say on same pole, back to back).
I can tell you Deb is overrun with bluebird pairs every year, and every other box is tree swallows…so the open location (though there are some phone wires nearby that you see them perch on, and there are trees not too far.
Shawn says
This is a terrific article — great advice and resources cited. Thanks.
Chris says
Diatomaceous Earth (must say food grade on label, industrial grade for pools has poison added) can be spread in nest boxes under nest or even sprinkled into nests to get rid of and prevent blowfly larvae. Safe for birds and even healthy for them. Farmers use it a lot to help control wetness and keep out or remove bugs in feed, bedding and even applied directly on animals. It will dehydrate/kill any bug, worm or larvae that comes in contact with it. Using it ahead of time in nest boxes helps prevent wetness and keeps larvae from even forming. D.E. is also used in kitty litter for clumping since it absorbs wetness. Often fed to animals and chickens to remove internal parasites of all kinds. High in healthy minerals and silica. Just make sure to use food grade only. Available at feed stores and health food stores as well as online.
margaret says
Thanks, Chris!
Roger Bergold says
I have had nesting bluebirds for several years. They are here all year round. I would like to clean out or even replace their house. It has been in the same spot for over a decade. Can I replace it now, without fear of damage to the birds?
PS made every mistake when I put the nesting box up. It faces north and is near a big oak tree. Yet, the blue birds seem to thrive. In fact, I have seen at least four of them together near the box.
I would appreciate your advice. Thanks
margaret says
Hi, Roger. I’d clean it right away, yes. If you plan to put a new house up, just have it ready to go so there is now “down time” I guess. Lucky you!
Jennifer Bertke says
Thank you for sharing your knowledge on bluebirding. I’m hooked and have referred to Bet’s site a great deal! I’d love to hear your thoughts on the following dilemma . . . morning time comes and a pair of bluebirds feed and sit on my box. The female pokes her head in the box and jumps in every few minutes. By the afternoon the bluebirds are gone and the HOSP is sitting on top of the box. They eventually hop in the box. I’ve read it’s too early for a sparrow spooker since the bluebirds haven’t laid any eggs yet. Help! I’m losing sleep!
margaret says
Sorry to miss this question till now, Jennifer. I just don’t know how one sorts out the birds wars; I watch the swallows and bluebirds duke it out in my garden every year, and don’t intervene. The Sialis website had some other recommendations, including using monofilament early — those ideas are at this link.